Hydroxyethyl cellulose (HEC) yog ib qho polymer uas tsis yog ionic, uas yaj tau hauv dej los ntawm cellulose, ib qho polymer ntuj uas pom muaj nyob rau hauv cov phab ntsa ntawm cov nroj tsuag. Nws yog siv dav hauv ntau yam lag luam, suav nrog cov tshuaj, cov tshuaj pleev ib ce, cov xim pleev, thiab cov nplaum, vim nws cov khoom zoo heev uas ua rau tuab, ua zaj duab xis, thiab cov khoom rheological. Kev npaj ntawm hydroxyethyl cellulose cuam tshuam nrog kev sib xyaw ntawm cellulose nrog ethylene oxide nyob rau hauv cov xwm txheej alkaline. Cov txheej txheem no tuaj yeem tawg ua ntau kauj ruam tseem ceeb: cellulose purification, alkalization, etherification, neutralization, ntxuav, thiab ziab.
1. Kev Ntxuav Cellulose
Kauj ruam thawj zaug hauv kev npaj hydroxyethyl cellulose yog kev ntxuav cov cellulose, feem ntau yog los ntawm cov ntoo pulp lossis paj rwb linters. Cov cellulose nyoos muaj cov khoom tsis huv xws li lignin, hemicellulose, thiab lwm yam extractives uas yuav tsum tau tshem tawm kom tau txais cov cellulose ntshiab siab uas tsim nyog rau kev hloov kho tshuaj.
Cov kauj ruam koom nrog:
Kev Ua Haujlwm Mechanical: Cov cellulose nyoos raug ua tiav los ntawm kev siv tshuab kom txo nws qhov loj me thiab ua kom nws thaj chaw ntau dua, ua rau kev kho tshuaj tom qab yooj yim dua.
Kev Kho Mob Tshuaj: Cov cellulose raug kho nrog cov tshuaj xws li sodium hydroxide (NaOH) thiab sodium sulfite (Na2SO3) kom tawg cov lignin thiab hemicellulose, ua raws li kev ntxuav thiab tshuaj dawb kom tshem tawm cov khoom seem thiab tau txais cov cellulose dawb, fibrous.
2. Kev ua kom alkalization
Cov cellulose uas tau lim lawm ces raug alkalized kom nws ua haujlwm rau qhov etherification reaction. Qhov no suav nrog kev kho cov cellulose nrog cov kua dej ntawm sodium hydroxide.
Kev teb:
Cellulose + NaOH → Alkali cellulose
Txheej Txheem:
Cov cellulose raug dai rau hauv dej, thiab cov kua sodium hydroxide raug ntxiv rau. Qhov concentration ntawm NaOH feem ntau yog li ntawm 10-30%, thiab cov tshuaj tiv thaiv tau ua tiav ntawm qhov kub ntawm 20-40 ° C.
Cov khoom sib tov no raug do kom ntseeg tau tias cov alkali nqus tau zoo ib yam, ua rau muaj cov alkali cellulose. Cov khoom nruab nrab no muaj kev cuam tshuam ntau dua rau ethylene oxide, ua rau cov txheej txheem etherification yooj yim dua.
3. Kev sib xyaw ua ke
Cov kauj ruam tseem ceeb hauv kev npaj hydroxyethyl cellulose yog qhov etherification ntawm alkali cellulose nrog ethylene oxide. Qhov kev tshuaj tiv thaiv no qhia cov hydroxyethyl pawg (-CH2CH2OH) rau hauv cellulose backbone, ua rau nws yaj hauv dej.
Kev teb:
Alkali cellulose + Ethylene oxide → Hydroxyethyl cellulose + NaOH
Txheej Txheem:
Ethylene oxide raug ntxiv rau hauv alkali cellulose, txawm tias ua ib pawg lossis ua tiav tas mus li. Feem ntau cov tshuaj tiv thaiv no ua nyob rau hauv lub tshuab autoclave lossis lub tshuab ua kom sov siab.
Cov xwm txheej ntawm cov tshuaj tiv thaiv, suav nrog qhov kub thiab txias (50-100 ° C) thiab siab (1-5 atm), raug tswj hwm kom zoo kom ntseeg tau tias muaj kev hloov pauv zoo tshaj plaws ntawm cov pab pawg hydroxyethyl. Qib ntawm kev hloov pauv (DS) thiab kev hloov pauv molar (MS) yog cov yam ntxwv tseem ceeb uas cuam tshuam rau cov khoom ntawm cov khoom kawg.
4. Kev tsis ua kom lub cev tsis ua haujlwm
Tom qab qhov kev sib xyaw ua ke ntawm etherification, cov khoom sib xyaw muaj hydroxyethyl cellulose thiab cov sodium hydroxide seem. Cov kauj ruam tom ntej yog neutralization, qhov twg cov alkali ntau dhau raug neutralized siv cov kua qaub, feem ntau yog acetic acid (CH3COOH) lossis hydrochloric acid (HCl).
Cov tshuaj tiv thaiv: NaOH + HCl → NaCl + H2O
Txheej Txheem:
Cov kua qaub no maj mam ntxiv rau hauv cov tshuaj sib tov hauv qab kev tswj hwm kom tsis txhob muaj cua sov ntau dhau thiab tiv thaiv kev puas tsuaj ntawm hydroxyethyl cellulose.
Cov khoom sib xyaw uas tsis muaj zog ces raug hloov kho pH kom ntseeg tau tias nws nyob hauv qhov ntau yam xav tau, feem ntau nyob ib puag ncig pH tsis muaj zog (6-8).
5. Ntxuav
Tom qab ua kom tsis muaj zog, cov khoom yuav tsum tau ntxuav kom tshem tawm cov ntsev thiab lwm yam khoom seem. Cov kauj ruam no yog qhov tseem ceeb rau kev tau txais hydroxyethyl cellulose ntshiab.
Txheej Txheem:
Cov tshuaj sib tov yog diluted nrog dej, thiab hydroxyethyl cellulose yog sib cais los ntawm kev lim dej lossis centrifugation.
Cov hydroxyethyl cellulose uas tau sib cais lawm raug ntxuav ntau zaus nrog dej deionized kom tshem tawm cov ntsev thiab cov khoom tsis huv uas seem. Cov txheej txheem ntxuav txuas ntxiv mus txog thaum cov dej ntxuav mus txog qhov conductivity uas tau teev tseg, qhia txog kev tshem tawm cov khoom tsis huv uas yaj tau.
6. Kev ziab
Kauj ruam kawg hauv kev npaj hydroxyethyl cellulose yog ziab. Kauj ruam no tshem tawm cov dej ntau dhau, ua rau cov khoom qhuav, hmoov uas haum rau ntau yam kev siv.
Txheej Txheem:
Cov hydroxyethyl cellulose uas ntxuav lawm ces muab nthuav rau ntawm cov tais ziab lossis xa mus rau hauv lub qhov ziab. Qhov kub ntawm qhov ziab raug tswj kom zoo kom tsis txhob muaj kev puas tsuaj los ntawm cua sov, feem ntau yog li ntawm 50-80°C.
Los yog, kev ziab tshuaj tsuag tuaj yeem siv rau kev ziab sai thiab zoo. Hauv kev ziab tshuaj tsuag, cov kua hydroxyethyl cellulose hauv dej raug atomized ua cov tee me me thiab ziab hauv cov cua kub, ua rau muaj hmoov zoo.
Cov khoom qhuav ces raug milled mus rau qhov loj me me uas xav tau thiab ntim rau kev khaws cia thiab faib tawm.
Kev Tswj Xyuas Zoo thiab Daim Ntawv Thov
Thoob plaws hauv cov txheej txheem npaj, cov kev ntsuas tswj hwm zoo raug siv los xyuas kom meej tias hydroxyethyl cellulose muaj qhov sib xws thiab zoo. Cov yam ntxwv tseem ceeb xws li viscosity, qib ntawm kev hloov pauv, cov dej noo, thiab qhov loj me ntawm cov khoom raug saib xyuas tas li.
Cov ntawv thov:
Cov Tshuaj: Siv ua tus neeg sawv cev thickening, binder, thiab stabilizer hauv cov formulations zoo li cov ntsiav tshuaj, cov suspensions, thiab cov tshuaj pleev.
Tshuaj pleev ib ce: Muab cov viscosity thiab cov qauv rau cov khoom xws li cream, lotions, thiab shampoos.
Xim thiab Txheej: Ua haujlwm ua tus thickener thiab rheology modifier, txhim kho cov khoom siv thiab kev ruaj khov ntawm cov xim.
Kev Lag Luam Khoom Noj: Ua haujlwm ua cov khoom ua kom tuab, stabilizer, thiab emulsifier hauv ntau yam khoom noj.
Kev npaj cov hydroxyethyl cellulose muaj ntau yam txheej txheem tshuaj lom neeg thiab tshuab uas tau txhais zoo uas tsom mus rau kev hloov kho cellulose kom qhia cov pab pawg hydroxyethyl. Txhua kauj ruam, los ntawm kev ntxuav cellulose mus rau kev ziab, yog qhov tseem ceeb hauv kev txiav txim siab qhov zoo thiab kev ua haujlwm ntawm cov khoom kawg. Hydroxyethyl cellulose cov yam ntxwv ua rau nws yog cov khoom xyaw tseem ceeb hauv ntau yam lag luam, qhia txog qhov tseem ceeb ntawm kev coj ua tsim khoom kom ua tau raws li cov kev xav tau tshwj xeeb ntawm ntau yam kev siv.
Lub sijhawm tshaj tawm: Tsib Hlis-28-2024